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D X Wang

Publications and source records attributed to D X Wang.

At least 37 records · Page 2Linked to original sources
PubMed1996

[Binding of [3H] dihydroetorphine to opioid receptors in rat brain membrane].

AIM: To study the binding characteristics of dihydroetorphine (DHE) to opioid receptors. METHODS: The binding of [3H] DHE to rat brain membrane opioid receptors was observed by radioligand binding study. RESULTS: Saturation study showed the binding of [3H] DHE to rat brain membrane presented a single high-affinity class of binding sites with Kd = 0.19 nmol.L-1 and Bmax = 115 pmol/g protein. Kinetics study showed the association rate of [3H] DHE to opioid receptor was very rapid and dissociation very slow. NaCl 100 mmol.L-1 + guanosine triphosphate (GTP) 50 mumol.L-1 inhibited the binding of [3H] DHE and made Kd increase to 7.87 nmol.L-1, without effect on Bmax. Competitive inhibition of agonists and antagonists indicated that the affinity of [3H]DHE to mu opioid receptor was higher than to delta and kappa opioid receptors. CONCLUSION: DHE is a selective agonist of mu opioid receptors.

Analgesics, Opioid↗
PubMed1995

Effects of 3,4-dihydroxyacetophenone (3,4-DHAP) on hypoxic pulmonary and systemic vascular response in dogs.

The effects of 3,4-DHAP on hypoxic pulmonary and systemic vascular responses were studied in anaesthetized dogs. The percentage change in pulmonary vascular resistance (delta PVR %) and that in systemic vascular resistance (delta SVR %) induced by 5 min hypoxia decreased significantly. 3,4-DHAP in doses of 1 mg/kg, 3 mg/kg, and 10 mg/kg i.v. caused a decrease in delta PVR% from the control value of 47.27 +/- 22.27% to 24.62 +/- 21.76%, 18.15 +/- 18.73%, and 24.10 +/- 19.76% respectively, and a decrease in delta SVR % from the control value of 12.91 +/- 7.39 % to -0.34 +/- 12.70%, -2.11 +/- 12.76%, and -2.37 +/- 15.52 % respectively. The results showed that 3,4-DHAP could decrease the hypoxic responses of pulmonary and systemic blood vessels. But it did not change delta PVR % or delta SVR % in dose of 30 mg/kg, neither did it influence the heart rate, cardiac output or cerebral blood flow during hypoxia in all the doses used.

Acetophenones↗
PubMed1995

Dihydroetorphine is a mu-receptor-selective ligand.

The selectivity to opioid receptors of dihydroetorphine, a potent analgesic with only mild physical dependence, was investigated using radioligand binding assay and its analgesic activity in mice determined. The relative affinity ratio of dihydroetorphine to mu-, delta- and kappa- opioid receptors was 333:1:1. The analgesic effect of intracerebro-ventricular injection in mice could be antagonized by the mu-antagonist beta-funaltrexamine but could not be antagonized by delta- and kappa-selective antagonists naltrindole and norbinaltorphimine. We conclude that dihydroetorphine is a selective ligand for the mu-opioid receptor.

Analgesics, Opioid↗
PubMed1994

Changes in cardiovascular activity during an increase in biliary tract pressure in rabbits.

In order to study the mechanism of decreased blood pressure caused by an acute increase in biliary tract pressure, we observed house rabbit model of self-made caecus for changes in cardiovascular function when biliary tract pressure was increased. It was found that both the blood pressure and cardiac output evidently decreased (P < 0.05) parallelly, and the systolic pressure decreased more markedly than diastolic pressure. At the same time there was fluctuation in heart rate and in central venous pressure; but there was no significant difference between them (P > 0.05), suggesting that in the absence of infective agents, the increased biliary tract pressure can bring about a decrease in cardiac output, which is an important factor contributing to an early blood pressure decrease in acute cholangitis of severe type (ACST).

Animals↗
PubMed1994

ATP evokes calcium transients in single pulmonary artery endothelial cell in primary cultures.

Effects of ATP on cytosolic free calcium ([Ca2+]i) in single porcine pulmonary artery endothelial cell were studied. Using a dual-wavelength excitation microflurometry, it was found that ATP evoked a rapid transient in [Ca2+]i which was then followed by a maintained elevation of [Ca2+]i. The removal of extracellular Ca2+ abolished the maintained plateform, but exerted no obvious effect on the initial-transient. These results suggest that ATP stimulates both calcium release from intracellular calcium pool(s) and calcium influx across the plasma membrane from extracellular space.

Adenosine Triphosphate↗
PubMed1994

Both hypoxic endothelial cell conditioned medium and hypoxia elevate intracellular free calcium in pulmonary artery smooth muscle cells.

By using Ca(2+)-sensitive fluorescent probe, Fura- 2, the effects of endothelial cell-conditioned medium and hypoxia on intracellular free calcium ([Ca2+]i) in cultured pulmonary artery smooth muscle cell (PASMC) were studied. Normoxic porcine pulmonary artery endothelial cell-conditioned medium (NPAECCM) obviously elevated [Ca2+]i in PASMC, whereas the hypoxic porcine pulmonary artery endothelial cell conditioned medium (HPAECCM) significantly elevated [Ca2+]i in PASMC much more than NPAECCM. Both the effects of NPAECCM and HPAECCM were dependent on the cultured endothelial cell extracellular calcium concentrations, ranged from 1.8 mmol/L to 2.4 mmol/L. Meanwhile, hypoxia directly increased, which was partially inhibited by verapamil, [Ca2+]i in PASMC through Ca2+ influx pathway. The data suggest that the augmented regulation of endothelial cell on PASMC via Ca2+ second messenger system and the hypoxia-induced Ca2+ influx into PASMC, particularly the former, may be components of mechanisms underlying hypoxic pulmonary vasoconstriction and chronic pulmonary hypertension.

Animals↗
PubMed1994

Effect of increasing biliary tract pressure on house rabbit blood dynamics in acute cholangitis of severe type.

In this study 12 Japanese long ear rabbits were used as models of acute cholangitis of severe type (ACST), and also an increasing pressure apparatus of self-made caecus to form high pressure of the biliary tract. The animals were observed for changes in blood dynamics in an attempt to explore the effect and relation of high pressure of biliary tract and infective element in pathogenesis of ACST. It was found that when the biliary pressure was increased within 120 min in the 20 kPa group, the blood endotoxin level showed no obvious increment (P > 0.05), but the decreased range of average MAP (mean artery pressure) was over 4 kPa, and the cardiac output also decreased evidently (P < 0.05), and that when the biliary pressure was decreased, MAP and cardiac output were restored to normal gradually. Of these animals 3 didn't restore their normal condition when the blood pressure decreased to zero and died finally. Meanwhile the electric discharge frequency of the right greater splanchnic nerves increased (P < 0.05), but when pressure was reduced, the frequency slowed down. From the above findings, the authors came to the conclusion that the rapid increase of the biliary tract pressure is the important factor leading to a decrease in blood pressure of ACST, and even bringing about irreversible shock, which is involved in the activity of splanchnic nerves.

Acute Disease↗
PubMed1994

Effects of 3,4-dihydroxyacetophenone on hypoxic vasoconstriction in isolated pulmonary and basilar arterial rings.

The effects of 3,4-DHAP on hypoxic vasoconstriction response in pulmonary (PA) and basilar arterial (BA) rings of rabbits and their mechanism were compared in vitro. 3,4-DHAP in different concentration (2.64 x 10(-4), 7.92 x 10(-4), 2.376 x 10(-3) mol/L) decreased the basal tone of PA rings by 32.39 +/- 9.4 mg, 68.96 +/- 26.54 mg and 145.60 +/- 58.07 mg respectively, while the tension of the BA rings was decreased by 13.80 +/- 5.08 mg, 17.18 +/- 3.36 mg and 25.00 +/- 4.02 mg respectively. In PA rings it also decreased the percentage increase in tension induced by hypoxia (TIH%) from the control value 48.82 +/- 5.75% to 10.02 +/- 3.62%, 2.14 +/- 0.96%, and 0.00% respectively, while in BA rings from 27.27 +/- 5.78% to 11.23 +/- 2.71%, 7.49 +/- 1.62%, and 1.45 +/- 1.13% respectively. The effects of 3, 4-DHAP on TIH% were partially blocked by indomethacin 10 M and L-NAME 10 M. The results showed that 3, 4-DHAP can decrease the hypoxic pulmonary and basilar vasoconstriction in vitro, which can be partially inhibited by cyclooxygenase inhibitor and NO/EDRF inhibitor.

Acetophenones↗
PubMed1994

Differences in ligand binding and phosphoinositide turnover between M1 muscarinic receptor gene transfected cells and mouse and rat brain membranes.

The present study describes some unexpected receptor mediated effects of N-methylcarbamylcholine on mouse M1 muscarinic receptor gene transfected cell line (M1Y1) that were not evident from biochemical studies with mouse and rat brain tissue where N-methylcarbamylcholine exhibited only nicotinic properties. Although N-methylcarbamycholine was devoid of muscarinic properties in mouse and rat brain preparations, as determined by phosphoinositide turnover and inhibition of [3H]QNB binding, it exhibited significant muscarinic characteristics in the transfected M1Y1 cell line. At a concentration of 10(-6) M or greater, N-methylcarbamycholine caused a transient increase in intracellular Ca2+ of 50 s duration that was reversible by atropine or pirezepine. The Ca(2+)-transient was not elicited by other nicotinic agents such as nicotine and N,N-dimethylcarbamylcholine, a close analogue of N-methylcarbamylcholine, with comparable affinity for nicotinic receptors and devoid of muscarinic activity. N-Methylcarbamylcholine also stimulated phosphoinositide turnover in M1Y1 cells with an estimated EC50 value 10 times greater than that of carbachol, and the effect was blocked by atropine. Both carbachol and N-methylcarbamycholine inhibited [3H]QNB binding in a concentration-dependent manner; however, the IC50 for carbachol was over two orders of magnitude greater than that observed in mouse and rat brain membranes. In considering possible explanations for the differential characteristics of N-methylcarbamylcholine in mouse and rat brain as compared to the transfected M1Y1 cells, it was concluded that the difference may be attributable to differences in the receptor-transduction coupling efficiency and the microenvironment of the muscarinic receptors.

Adrenal Glands↗
PubMed1994

Establishment of a human malignant T lymphoma cell line carrying retrovirus-like particles with RT activity.

We have established an IL-2 independent malignant lymphoma line (CM-1) from peripheral T lymphocytes donated by a female patient with nervous system disease, the biological characteristics of CM-1 cells was studied in this paper. Another T lymphocytes, such as peripheral T lymphocytes donated by a male patient with multiple sclerosis, could be transformed into a malignant lymphoma line by using filtered supernatant of the CM-1 cultured medium, thus the CM-2 cell line was established. The CM-1 and CM-2 cells were transplanted by subcutaneous inoculation into nude mice, and could cause the occurrence of typical malignant lymphoma. The observation of electron micrographs suggested the existence of virions in the CM-1 and CM-2 cells, and these virions were similar to retrovirus in the ultra-structure characteristics. It was found that this virus possesses reverse transcriptase activity. Results obtained from serological assay, molecular hybridization and PCR excluded the existence of other human viruses, which were commonly used in our laboratory. The unknown virus possesses strong transformation activity, and probably is a new retrovirus. Meanwhile, the work on the clone and sequence analysis of this virus are being carried out.

Adult↗
PubMed1994

[Experimental research on treatment of acute organophosphorus insecticides poisoning with high-dose atropine: upregulation of muscarinic receptor].

Acute organophosphorus insecticides poisoning (AOIP) is a common medical emergency. There is, at present, a tendency to use high-dose atropine treatment (HDAT). This study aims to test if, during AOIP, HDAT would cause upregulation of muscarinic receptor (M-R). Male mice of the same batch and strain were raised, randomly divided into 3 groups and orally fed with DDVP of the same dose. HDAT for 7 days was given to group A, HDAT for 36 hours was given to group B and low-dose atropine treatment for 36 hours was given to group C. Then radionuclide assay was employed to measure the M-R in the brain and atrium of the mice in each group. The results were that, compared with a control group, the Bmax values (fmol.mg protein-1) of M-R in groups A and B were increased significantly (P < 0.01), while that in group C showed no evident change (P > 0.05). These results indicate that HDAT leads to some physiological change in the body, which may be responsible for the development of poisoning rebound and atropine dependence.

Animals↗
PubMed1994

[Atropine dependence during treatment of acute organophosphorus pesticides poisoning].

In treating patients with acute organophosphorus pesticides poisoning, clinicians pay more attention to poisoning counterattack, while atropine dependence, which resembles counterattack, is not yet fully recognized. The authors analysed 1,039 patients with this kind of poisoning treated in 7 years. Among these cases 157 were dependent on atropine, consisting of 15.1% of the total. The clinical manifestations of the dependence were described. The diagnostic criteria of the dependence and its differential points from counterattack were suggested. It was found that higher occurrence rate of the dependence was seen in patients of younger age, with more severe poisoning and with longer duration and higher total dose of atropine treatment (P < 0.005 respectively). It is considered that its mechanism might be related to increased number of M-receptor and excessive accumulation of acetylcholine. It is suggested that quantitative analysis of relevant receptor be developed.

Adolescent↗
PubMed1994

[Effect of ATP on cytosolic free calcium in single porcine pulmonary artery endothelial cell in primary culture].

Effect of ATP on cytosolic free calcium ([Ca2+]i) in single porcine pulmonary artery endothelial cell was studied. Using a dual-wavelength excitation fluorescence spectrophotometer, it was found that ATP evoked a rapid rise in [Ca2+]i followed by a slightly maintained increase. Removal of extracellular Ca2+ abolished the maintained increase without obvious effect on the initial transient. These results suggest that ATP stimulates both calcium release from intracellular calcium pool (s) and calcium influx across the plasma membrane.

Adenosine Triphosphate↗
PubMed1994

[Effect of gonadotropin-releasing peptide (GRP) on LH secretion of mouse pituitary in vitro].

Synthetic GRP and its analogues, GRP-NH2, [Glu7.9.14 Lys6.10] GRP (6-14), [Phe14] GRP (5-14) and [Phe14] GRP, at the concentration of 0.05 mmol.L-1 were shown to have stimulatory effect on LH secretion in cultured mouse pituitary in vitro. The luteotropin releasing activity of GRP and its analogues was estimated to be 115.4, 114.2, 140.0, 162.0 and 179.0% of the control group, respectively. Subcutaneous administration of [Phe14] GRP on days 7-9 and 1-5 of pregnancy and [Phe14] GRP (5-14) on days 2-4 of gestation at dosage of 1 mg.d-1 (each mouse) caused fetal death in 40-60% of mice.

Abortifacient Agents↗
PubMed1994

[Synthesis of tyrosine-related peptide and their effect on progesterone production].

Twenty peptides containing hydroxy-amino acids have been synthesized manually by stepwise solid-phase procedure. The chloromethyl resin and MBHA resin were used as solid supports. A new reagent of 0.5 mol.L-1 DDSi/1.5 mol.L-1 phenol/DCM was applied for the removal of N alpha-Boc group. TFMSA was the cleaving reagent. After purification by C-18 column; all products were assayed according to amino acid analysis. The bioactivity of synthetic peptides was tested for the effect on progesterone production in vitro. Eight peptides, GlyTyrAlaLys, (SarSer)2Lys and its methyl ester, TyrLys, HisTyr-NH2, ThrProTyrLys-NH2 TyrThrProArgLys and AspHisProThrPheLys showed significant effect on inhibiting hCG-induced progesterone production, and first three of them could also inhibit basal progesterone secretion. However, peptide GlySerTyr exhibited stimulative activity on basal progesterone secretion. So far, no reasonable relationship between structure and bioactivity was found.

Animals↗